10 research outputs found
Análise multivariada de parâmetros físicos, químicos e biológicos da água da Baía de Guanabara - RJ [gráficos]
Análise multivariada de parâmetros físicos, químicos e biológicos da água da Baía de Guanabara - RJ [mapas]
Relationships between bacterial diversity and environmental variables in a tropical marine environment, Rio de Janeiro
11 p. : il.This study is the first to apply a comparative analysis of environmental chemistry, microbiological parameters and bacterioplankton 16S rRNA clone libraries
from different areas of a 50 km transect along a trophic gradient in the tropical Guanabara Bay ecosystem. Higher bacterial diversity was found in the coastal area, whereas lower richness was observed in the more polluted inner bay water. The significance of differences between clone libraries was examined with LIBSHUFF statistics. Paired reciprocal comparisons indicated that each of the libraries differs significantly from the others, and this is in
agreement with direct interpretation of the phylogenetic tree. Furthermore, correspondence analyses showed that some taxa are related to specific abiotic, trophic and microbiological parameters in Guanabara Bay estuarine system
Bacterial communities of the marine sponges Hymeniacidon heliophila and Polymastia janeirensis and their environment in Rio de Janeiro, Brazil
12 p. : il.In this study we performed a survey of the
bacterial communities associated with the Western Atlantic demosponges Hymeniacidon heliophila and Polymastia janeirensis, based on 16S rRNA sequencing and transmission
electron microscopy (TEM). We compared diversity and composition of the sponge-associated bacteria to those of environmental bacteria, represented by free-living bacterioplankton and by bacteria attached to organic particulate matter in superWcial sediments. Partial bacterial 16S rRNA sequences from seawater, sediment, and sponges were retrieved by PCR, cloning, and sequencing. Sequences were subjected to rarefaction analyses, phylogenetic tree
construction, and LIBSHUFF quantitative statistics to verify coverage and similarity between libraries. Community structure
of the free-living bacterioplankton was phylogenetically different from that of the sponge-associated bacterial assemblages. On the other hand, some sediment-attached
bacteria were also found in the sponge bacterial community, indicating that sponges may incorporate bacteria together with sediment particles. Rare and few prokaryotic
morphotypes were found in TEM analyses of sponge mesohyl matrix of both species. Molecular data indicate that bacterial richness and diversity decreases from bacterioplankton, to particulate organic sediment, and to H. heliophila and P. janeirensis. Sponges from Rio de Janeiro
harbor a pool of novel and exclusive sponge-associated bacterial taxa. Sponge-associated bacterial communities are composed of both taxons shared by many sponge groups and by species-speciWc bacteria
Diversity of bacterial communities related to the nitrogen cycle in a coastal tropical bay
7 p. : il.A culture-independent molecular phylogenetic
analysis was carried out to study for the first time the diversity of bacterial ammonia monooxygenase subunit A (amoA) and nitrogenase reductase subunit H (nifH) genes
from Urca inlet at Guanabara Bay in Rio de Janeiro, Brazil.
Most bacterial amoA and nifH sequences exhibited identities of less than 95% to those in the GenBank database revealing that novel ammonia-oxidizing bacteria and nitrogen-fixing microorganisms may exist in this tropical marine environment. The observation of a large number of clones related to uncultured bacteria also indicates the necessity to describe these microorganisms and to develop new cultivation methodologies
Archaeal and bacterial communities of heavy metal contaminated acidic waters from zinc mine residues in sepetiba bay
9 p. : il., tab.Mining of metallic sulfide ore produces acidic
water with high metal concentrations that have harmful
consequences for aquatic life. To understand the composition
and structure of microbial communities in acid mine
drainage (AMD) waters associated with Zn mine tailings,
molecular diversity of 16S genes was examined using a
PCR, cloning, and sequencing approach. A total of 78
operational taxonomic units (OTUs) were obtained from
samples collected at five different sites in and around
mining residues in Sepetiba Bay, Brazil. We analyzed metal
concentration, physical, chemical, and microbiological
parameters related to prokaryotic diversity in low metal
impacted compared to highly polluted environments with
Zn at level of gram per liter and Cd–Pb at level of microgram
per liter. Application of molecular methods for
community structure analyses showed that Archaea and
Bacteria groups present a phylogenetic relationship with
uncultured environmental organisms. Phylogenetic analysis
revealed that bacteria present at the five sites fell into seven
known divisions, a-Proteobacteria (13.4%), b-Proteobacteria
(16.3%), c-Proteobacteria (4.3%), Sphingobacteriales
(4.3%), Actinobacteria (3.2%) Acidobacteria (2.1%),
Cyanobacteria (11.9%), and unclassified bacteria (44.5%).
Almost all archaeal clones were related to uncultivated
Crenarchaeota species, which were shared between high
impacted and low impacted waters. Rarefaction curves
showed that bacterial groups are more diverse than archaeal
groups while the overall prokaryotic biodiversity is lower in
high metal impacted environments than in less polluted
habitats. Knowledge of this microbial community structure
will help in understanding prokaryotic diversity, biogeography,
and the role of microorganisms in zinc smelting
AMD generation and perhaps it may be exploited for
environmental remediation procedures in this area
Prokaryotic diversity in one of the largest hypersaline coastal lagoons in the world
10 p. : il.Araruama Lagoon is an environment characterized by high salt concentrations. The low raining and high evaporation rates in this region favored the development
of many salty ponds around the lagoon. In order to reveal the microbial composition of this system, we performed a 16S rRNA gene survey. Among archaea, most clones were related to uncultured environmental Euryarchaeota.
In lagoon water, we found some clones related
to Methanomicrobia and Methanothermococcus groups, while in the saline pond water members related to the genus Haloarcula were detected. Bacterial community was dominated by clones related to Gamma-proteobacteria,
Actinobacteria, and Synechococcus in lagoon water, while Salinibacter ruber relatives dominated in saline pond. We also detected the presence of Alpha-proteobacteria, Pseudomonas- like bacteria and Verrucomicrobia. Only representatives of the genus Ralstonia were cosmopolitan, being observed in both systems. The detection of a substantial number of clones related to uncultured archaea and bacteria suggest that the hypersaline waters of Araruama harbor a pool of novel prokaryotic phylotypes, distinct from those observed in other similar systems. We also observed clones related to halophilic genera of cyanobacteria
that are specific for each habitat studied. Additionally, two bacterioplankton molecular markers with ecological relevance were analyzed, one is linked to nitrogen fixation
(nifH) and the other is linked to carbon fixation by bacterial photosynthesis, the protochlorophyllide genes, revealing a
specific genetic distribution in this ecosystem. This is the first study of the biogeography and community structure of
microbial assemblages in Brazilian tropical hypersaline environments. This work is directed towards a better understanding of the free-living prokaryotic diversity
adapted to life in hypersaline waters
Coastal bacterioplankton community diversity along a latitudinal gradient in Latin America by means of V6 tag pyrosequencing
10 p. : il.The bacterioplankton diversity of coastal
waters along a latitudinal gradient between Puerto Rico and Argentina was analyzed using a total of 134,197 high-quality sequences from the V6 hypervariable region of the small-subunit ribosomal RNA gene (16S rRNA) (mean length of 60 nt). Most of the OTUs were identified into Proteobacteria, Bacteriodetes, Cyanobacteria, and Actinobacteria, corresponding to approx. 80% of the total number of sequences. The number of OTUs corresponding to species varied between 937 and 1946 in the seven locations.
Proteobacteria appeared at high frequency in the seven locations. An enrichment of Cyanobacteria was observed in Puerto Rico, whereas an enrichment of Bacteroidetes was detected in the Argentinian shelf and Uruguayan coastal lagoons. The highest number of sequences of Actinobacteria and Acidobacteria were obtained in the Amazon estuary mouth. The rarefaction curves and Good coverage estimator for species diversity suggested a significant coverage, with values ranging between 92 and 97% for
Good coverage. Conserved taxa corresponded to aprox. 52% of all sequences. This study suggests that human contaminated environments may inXuence bacterioplankton
diversity